Coupler with Magnet

ABSTRACT

A coupler includes first and second attachment pin jaws. A first latching mechanism is associated with the first jaw. The first latching mechanism has an arm connected to and extending away from a latching member. A second latching mechanism is associated with the jaw. The first and second latching mechanisms are adapted to latch the first and second attachment pins of an accessory in or on the first jaw and the second jaw, respectively. The second latching mechanism is powered for movement between a latching position and a non-latching position. The first latching mechanism is operatively connected to, or connectable with, the second latching mechanism to allow it to selectively operate the first latching mechanism between latching and non-latching positions by means of a groove or flange or finger on the second latching mechanism. A magnet is provided to ensure a correct disengagement of the first latch latching mechanism.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to UK Patent Application No. 1104041.7 filed Mar. 9, 2011, the entire disclosure of which is expressly incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A “SEQUENCE LISTING”

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a coupler for attaching an accessory, such an excavator bucket, to an excavator arm of an excavator. In particular, it relates to a fully automatic coupler for attachment, at its top half, to an excavator arm, and having, in its bottom half, two jaws and two latches for selectively securing (or releasing) two attachment pins of an accessory in (or from) the jaws of the coupler.

2. Description of Related Art

Not applicable.

BRIEF SUMMARY OF THE INVENTION

Many different couplers for attaching accessories to an excavator arm of an excavator have been developed. Many of those have been either manual or semi-automatic in function, i.e. requiring one or more manual steps to be carried out at the coupler in order to complete or commence the attachment or removal of an accessory onto or from the coupler. An increasing drive, however, is towards providing a fully automatic coupler. Such couplers allow the full securement and release procedure, i.e. for securing or releasing an accessory onto or from the coupler, by the operator from within the cab of the excavator, e.g. via controls provided in the cab.

There is also a further problem with couplers of this type—users occasionally use them incorrectly. Therefore, there is a further drive in the art to provide couplers that either prevent incorrect usage, or which counter incorrect usage by making such usage less dangerous by the provision of secondary or tertiary locking mechanisms, in addition to the primary locking mechanism provided by a latching hook, so as to provide mechanical back up mechanisms for preventing inadvertent release of the accessory from the coupler in the event of an improper use of the coupler.

There is also an issue with couplers in that with the automated operation, misalignment of elements within the coupler, due to operator shortcuts, can lead to errors in either or both of the coupling and decoupling procedures, whereby the coupling or decoupling procedure will not complete successfully, thereby leading to repeated attempts at coupling/decoupling, and thus lost operator time.

The present invention therefore seeks to provide a fully automatic coupler having back-up operator control mechanisms incorporated therein, and one in which short-cuts taken by the operator are less likely to lead to a coupling (or decoupling) failure.

According to the present invention there is provided a coupler having a top half for attaching to an end of an excavator arm of an excavator and a bottom half for attaching to an accessory, the bottom half comprising first and second jaws, at least one of the jaws featuring an associated latching mechanism for retaining an attachment pin of the accessory within the jaw, wherein the coupler further comprises a magnet for releasably engaging or holding a component of the locking mechanism.

By the presence of the magnet, the component of the locking mechanism (be it the latch, an element extending therefrom, or a device for engaging that latch or element) can be selectively held in (or selectively pulled into) a predetermined position or orientation relative to the frame of the coupler, by magnetic attraction, either or both during a step in a coupling procedure or during a step in a decoupling procedure. The magnet can therefore assist in preventing short-cuts (e.g. incomplete powered movements of components) from leading to a misalignment of elements within the coupler during those steps, since the magnet will compensate a short-cut by pulling or holding the component in the required position, rather than just the position that would otherwise have been achieved by the operator's operation.

Preferably, the magnet is a permanent magnet. It might, however, be an electromagnet.

The coupler's first jaw may have an opening pointing generally level with the longitudinal axis of the coupler, i.e. in a nominally forwards direction with respect to the coupler. It is for receiving a first attachment pin of the accessory. This may potentially be the attachment pin referred to above.

The coupler's second jaw may have an opening pointing generally perpendicular to the longitudinal axis of the coupler, i.e. nominally downwards with respect to the coupler. It is for receiving a second attachment pin of the accessory. This may alternatively be the attachment pin referred to above.

Preferably, a latching mechanism is associated with the first jaw, the first latching member having an arm operatively connected to and extending away from a latching member thereof. This may be the associated latching mechanism referred to above.

Preferably a latching mechanism is associated with the second jaw. This may alternatively be the associated latching mechanism referred to above.

Preferably the two latching mechanisms are both provided. Only one though would be associated with the magnet. It is possible though for more than one magnet to be provided, with each latching mechanism being associated with one of those magnets. With two latching mechanisms, the first and second latching mechanisms are adapted to latch first and second attachment pins of the accessory in or on the first jaw and the second jaw, respectively.

The accessory may be a bucket, or some other excavator tool.

Preferably the second latching mechanism is powered for movement between a latching position and a non-latching position.

Preferably the first latching mechanism is operatively connected to, or connectable with, the second latching mechanism to allow operation of the second latching mechanism selectively to operate the first latching mechanism between its own latching and non-latching positions.

Preferably the second latching mechanism is provided with a groove or flange or finger for defining a space or surface in or on which a free end of the arm of the first latching mechanism can reside during either or both a coupling and/or a decoupling procedure of the coupler for allowing the movement of the second latching mechanism to operate the first latching mechanism between its latching position and its non-latching position.

This arrangement may also be used to release or commence the hold or pull of the magnet by selectively powering the component towards or away from the magnet.

Preferably the groove, flange or finger allows the movement of the second latching mechanism to operate the first latching mechanism both from its latching position into its non-latching position and from its non-latching position into its latching position.

Preferably the second latching mechanism is powered by a hydraulic cylinder between its latching position and its non-latching positions. Most preferably the hydraulic cylinder is powerable in either direction—i.e. it is a dual action cylinder for opening the coupler (in an uncoupling procedure), and for closing the coupler (in a coupling procedure).

Preferably the first latching mechanism has a latching face adapted at least partially to close the first jaw of the coupler when the first latching mechanism is in a latching state.

Preferably, as the second latching mechanism is powered into a non-latching position, the free end of the arm of the first latching mechanism, upon engagement by the second latching mechanism, is lifted by the movement of the second latching mechanism, so as to lift, for example, the latching face of the first latching mechanism out of the mouth of the first jaw, i.e. into a non-latching position.

Preferably the flange or finger is provided at the rear of the second latching mechanism, that flange or finger being arranged so as to engage the free end of the arm extending from the first latching mechanism. With this arrangement, as the second latching mechanism is powered into a latching position, the arm is engaged by that flange or finger so as to drive the first latching mechanism back into its latching position.

Preferably the or each latching mechanism is associated with a blocking bar. The blocking bar is preferably adapted to default, under the influence of gravity, into a blocking position, e.g. behind its latching mechanism, when the coupler is in a generally horizontal orientation, such as where its front jaw's opening faces horizontally.

Preferably the or each blocking bar is adapted to fall under the influence of gravity into a non-blocking position when the coupler is rotated into a crowd position. Such a crowd position can be achieved by manipulation of the excavator, i.e. its hydraulics and its excavator arm, from within the cab of the excavator.

A separate actuator, however, might instead be provided for the blocking bar. This allows the blocking bar still to be independently operable from the cab of the excavator, i.e. independent of the actuator for the latching hook.

The blocking bar may be the component of the latching mechanism, such that the magnet is for releasably engaging or holding a the blocking bar.

A spring bias may be provided to bias the blocking bar into or towards a blocking position. The spring bias may be releasable, such as when the coupler is powered into a crowd position. The spring bias may take the form of a leaf spring. It may selectively engage against the arm of the excavator during use of the coupler.

Preferably the spring is attached to the blocking bar and it has a free end that selectively bears, in use, against the excavator arm of the excavator such that it can act selectively, e.g. while the coupler, with respect to the excavator arm, is in a fully extended (non-crowd) condition, i.e. at an opposite extreme of rotation relative to the excavator arm as compared to the crowd position. The spring would then be selectively disengaged when the coupler is in a crowd position relative to the excavator arm. As a result, the blocking bar can be disengaged from the second latching mechanism, using gravity, only when the coupler is both inverted and in the crowd position—the crowd position allows the spring to disengage from operation, and the inversion causes gravity to do the rest. The disengagement will thus not occur when the coupler is inverted in a non-crowd position, such as while in a fully extended condition with respect to the excavator arm.

Such a coupler, therefore, is designed such that a disengagement of an accessory should only be possible while the coupler is both inverted and in a crowd position with respect to the excavator arm.

In an alternative embodiment, the blocking bar may be arranged such that it is always biased towards a blocking position. For example, this may be achieved with a spring that permanently acts against the blocking bar. That spring may be a conventional coil spring attached between the frame of the coupler and the blocking bar, or extending between the frame, or some other part of the coupler (e.g. the rear latching mechanism or hook), and the blocking bar. For example, it may be coiled around a pivot pin for the rear latching mechanism (or a pivoting hook thereof), with free arms thereof extending one down the back of the hook and the other towards the blocking bar for engaging near a free end thereof. Preferably, however, it is a spring that is concealed within the blocking bar so as to be protected from dirt ingress—a dirty spring can more readily fail than a clean spring (e.g. as a result of the coils not being able to spring together due to dirt between the coils). Alternatively it might be integral with the blocking bar.

Where the blocking bar is permanently biased towards a blocking position, it is preferred that a counter-biasing means is provided for selectively overcoming that permanent bias for moving the blocking bar against the permanent bias towards a non-blocking position. Thus, upon activation of the counter-biasing means (e.g. a second actuator, such as a hydraulic ram), the blocking bar can be remotely lifted into a non blocking position. Such a counter-biasing means is especially needed where the spring bias is such that upon inverting the coupler, the blocking bar's own weight is insufficient to overcome the force of that permanent bias. With this arrangement, the blocking bar can be lifted without inverting the coupler, which allows the coupler to be used for switching accessories on the excavator even in environments where the crowd position cannot be achieved (such as in areas with a low ceiling—e.g. in tunnels; the arm of the excavator needs to point it's elbow generally upwards when the crowd position for the accessory is being achieved).

Preferably the counter biasing means is operated via a separate switch to the actuator provided for powering the second latching mechanism. That switch may be in the cab of the excavator, alongside or near the other switches for the coupler.

Regarding the counter-biasing means, that is preferably a hydraulic ram, and it preferably has a separate hydraulic feed to the coupler's primary actuator (the actuator for powering the second latching mechanism). This allows the two actuators to be controlled independently of one another. This is important for preventing inadvertent release of the blocking bar. A common hydraulic return, however, can be provided.

Preferably the two actuators are operated by separate switches in the cab of the excavator, each switch operating a separate solenoid for controlling two separate feed-pipes, one heading to the primary actuator (e.g. for the latching mechanism, or the hook thereof, and the other heading to the actuator that acts against the blocking bar for moving that blocking bar.

With this alternative blocking bar arrangement, an accessory can be disengaged from the coupler either while inverted or non-inverted. As discussed, however, that piston, preferably operates via a separate hydraulic feed to the main hydraulic cylinder or actuator of the coupler, i.e. the actuator for operating the rear hook/latching means.

In a further development of this, the actuator for the blocking bar can be fitted with a tilt detection circuit for preventing operation thereof when the coupler is not inverted. Likewise, a separate blocking bar for the blocking bar can be provided to prevent a movement of the blocking bar into a non blocking position other than when a rotation of the coupler is provided in an “into the crowd position” direction. Time delays on the actuator for the blocking bar might also be integrated into the system, whereby only upon holding a control switch in a decoupling position for a long enough period of time will a decoupling procedure commence. This prevents accidental one-touch decouplings.

Alternatively, or additionally, the arm of the first latching mechanism can act as a blocking bar, by way of its free end being arranged relative to the rear of the second latching mechanism such that it would bear against a non-arm-lifting part of the second latching mechanism for preventing release of the accessory prior to an inversion of the coupler. It might even be provided with a lift mechanism or a biasing means such as that described above for the blocking bar. Preferably, however, the powered blocking bar arrangement is instead provided as a separate or independent locking mechanism to the front latch/arm.

Preferably the coupler is arranged or designed so as not to require an inversion prior to release of an accessory. As such, the free end of the arm is preferably arranged to engage with the groove, flange or finger of the second latching mechanism in a non-blocking manner relative to the second latching mechanism, i.e. such that a powering back of the second latching mechanism from a latching position into a non-latching position will always cause the first latching mechanism to be lifted into a non latching position. For that purpose, the rear of the second latching mechanism can be suitably profiled to provide an arm-lifting surface, e.g. by the provision of a ramp on its back, or some other suitably angled surface for engagement with the free end of the arm as the second latching mechanism is powered into an open configuration. The arm can even be made to flex upwardly into an arch, e.g. by being made of an elastic material, such as spring steel, or a set of spring steel plates, as it gets engaged by the end facing surface of the second latching mechanism. Such an arching of the arm can then rotate the latching part of the first latching mechanism for lifting that latching part of the first latching mechanism into an open (non-latching) position.

Preferably the first latching mechanism comprises a rocker latch for partially closing the first jaw when in a “dropped” or jaw closing position.

Preferably the arm extends from the rocker latch or a latching plate thereof.

Preferably the arm of the first latching mechanism extends within the coupler inside the framework or frame of the coupler.

Preferably the arm extends towards the second latching mechanism. Usually this results in it extending away from the first jaw.

Preferably the arm is formed of an elastic material, such as spring steel, or a set of spring steel plates. The arm can then flex, thus allowing an accessory pin to be inserted into the first jaw without first opening the second jaw by forcing the accessory pin into the first jaw. The first latching mechanism can have a tapered front face for facilitating this. The elasticity in the material also prevents the arm from breaking, or deforming non-elastically, i.e. plastically, if the second latching mechanism is powered into a latching position while the first latching mechanism is not able to assume its own latching mechanism due to, for example, a blockage, e.g. if the attachment pin within the first jaw is not fully seated within that jaw, thereby lying in the path of the first latching mechanism. Movement of the second latching mechanism into its latching position, however, will force the accessory rearwardly relative to the coupler, by way of its interaction with the other attachment pin, thereby moving that first attachment pin properly into the back of the first jaw. The first latching mechanism would thus assume its latching position, due to the bias provided by its arm against the groove, flange or finger of the second latching mechanism, once the accessory has moved sufficiently rearwardly to remove the blockage caused by that attachment pin within the first jaw.

Preferably the arm is the component that the magnet can releasably engage or hold.

Preferably the first latching mechanism has a component, visible through the opening of a front jaw of the coupler, that is painted in a high visibility color, such as red or yellow or orange.

Preferably the first latching mechanism is pivotally mounted relative to the frame of the coupler. Preferably it is mounted to the frame on a pivot pin.

Preferably the second latching mechanism is pivotally mounted relative to the frame of the coupler. Preferably it is mounted to the frame on a pivot pin.

Preferably the second latching mechanism consists of a hook member.

Preferably the flange, finger or groove extends from or into a rear surface of the second latching mechanism.

Preferably a rear surface of the second latching mechanism is stepped in an area thereof, each step defining a location against which a free end of a blocking bar may bear. This is to allow multiple different blocking positions for the blocking bar. This permits the coupler to be used safely on a variety of different accessories, each having different accessory pin centers (distances between the pin centers).

Preferably the rear of the second latching mechanism is bifurcated with one side of the fork providing a location for the flange, finger or groove.

Preferably the second side of the fork defines one or more surface against which a free end of a blocking bar may bear. The one or more surfaces may be provided by means of steps.

The jaws may be a front jaw and a rear jaw. The rear jaw, which may have an opening pointing generally perpendicular to the longitudinal axis of the coupler, may have opening height that is at least 1.8 times that of the opening height of the front jaw.

A further safety feature may be incorporated—the use of a safety pin. A safety pin may be implemented for either of the front latch or the rear latch, or for the blocking bar, for locking or securing that latch or blocking bar in a locked or latched position.

Both latches may be provided with associated safety pins.

The safety pin or pins may pass through either one or both of the sidewalls of the frame of the coupler for engagement against a surface of the associated latch, thereby preventing retraction of that latch into a non-latching position with respect to a pin in the associated jaw. That surface of the latch may be an external (or rear) surface of the latch. In an alternative embodiment, that surface could be an internal surface of the latch.

The latch, pin or coupler could be adapted to lock the latch in any one of multiple pin locking positions for accommodating and securing accessories having different pin spacings. For example, multiple holes may be provided in the coupler's sidewall, or in the coupler's side walls, whereby a pin can be positioned in the most appropriate hole or spaced pair of holes, for locking or securing the associated latch in the most appropriate latched position for a given pin spacing. Alternatively, or additionally, a hole can be provided in the associated latch (or latch mechanism), whereby a single hole or pair of holes can be used to lock or secure the latch in either one of two positions—one using the hole—an internal surface of the latch—and the other using the rear of the latch—the external surface of the latch. Combinations of the above might also be provided.

The pin may also be adapted to have a non circular cross section, whereby the shape of the pin allows it to lock or secure the latch in a variety of different locking positions dependent upon the orientation of the pin within a given hole or pair of holes.

According to a further aspect of the present invention there is provided a coupler having a top half for attaching to an end of an excavator arm of an excavator and a bottom half for attaching to an accessory, the bottom half comprising first and second jaws, both of the jaws featuring an associated latching mechanism for retaining an attachment pin of the accessory within the associated jaw, wherein the coupler further comprises safety pin for securing at least one of the latching mechanisms in a latching state with respect to the associated attachment pin.

The latching mechanisms may be as defined above with respect to any one or more of the features of the earlier aspects of the invention. For example, at least one of them may be power actuated, or they may both be power actuated. For example each latching mechanism may be independently power actuated with respect to the other.

The two jaws may be a front jaw and a rear jaw. The rear jaw would usually be power actuated.

The safety pin may be implemented for either of the latching mechanisms. It is possible, alternatively, for both latching mechanisms to be provided with associated safety pins.

The safety pin or pins may pass through either one or both sidewalls of a frame of the coupler for engagement against a surface of the associated latching mechanism, thereby preventing retraction of that latching mechanism into a non-latching position with respect to an attachment pin in the associated jaw. That surface of the latching mechanism may be an external (or rear) surface of the latching mechanism—one facing away from an attachment pin engaging surface of the latching mechanism. In an alternative embodiment, that surface could be an internal surface of the latch, such as a surface of a hole in the latching mechanism.

The latching mechanism, the safety pin or the coupler could be adapted to lock the latching mechanism in any one of multiple pin locking positions for accommodating and securing accessories having different attachment pin spacings. For example, multiple holes may be provided in the coupler's sidewall, or in the coupler's sidewalls, whereby a safety pin can be positioned in the most appropriate hole or spaced pair of holes, for locking or securing the associated latching mechanism in the most appropriate latched position for a given attachment pin spacing. Alternatively, or additionally, a hole can be provided in the associated latching mechanism, whereby a single hole or pair of holes can be used to lock or secure the latching mechanism in either one of two positions—one using the hole—an internal surface of the latch—and the other using the rear of the latch—the external surface of the latch. Combinations of the above might also be provided to increase the number of options in terms of secured latching positions.

The safety pin may also be adapted to have a non circular cross section at the area in which it engages the latching mechanism, whereby the shape of the safety pin allows it to lock or secure the latching mechanism in a variety of different locking positions dependent upon the orientation of the safety pin within a given hole or pair of holes. For example, the safety pin may have a rectangular section in its middle.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

These and other features of the present invention will now be described, purely by way of example, with reference to the accompanying drawings in which:

FIG. 1 schematically shows a breakaway perspective view of the internal working mechanisms of a coupler in accordance with the present invention;

FIG. 2 shows a schematic cutaway side elevation of the coupler of FIG. 1 rotated into a crowd position, with its first and second latching mechanisms fully retracted;

FIG. 3 shows the coupler of FIG. 2, but reoriented and engaged upon a first accessory pin of an accessory, such as an excavator bucket;

FIG. 4 shows the same coupler again, but now rotated relative to that bucket to engage the second accessory pin in the rear jaw of the coupler, and having had the second latching mechanism driven into a latching position;

FIG. 5 shows the same coupler, now with the two accessory pins safely secured within the jaws of the coupler—the blocking bar has been engaged behind the rear of the second latching mechanism, and the front latching mechanism is resting in a latching condition for the front jaw;

FIG. 6 shows step 1 of an accessory removal procedure, in which the coupler has been moved into a crowd position for disengaging the blocking bar, by means of which the second latching mechanism can be retracted by the hydraulic cylinder to open both of the jaws (the weight of the bucket retains the bucket's first accessory pin within the front jaw of the coupler whereby the bucket cannot fall off the coupler);

FIG. 7 shows step 2 in the accessory removal procedure, in which the bucket has been placed on the ground by lowering and uncrowding the coupler, and in which and the coupler has then been moved away from the bucket;

FIG. 8 further illustrates the safety mechanisms of the present invention for preventing an inadvertent decoupling of an accessory even upon an incorrect or missed engagement of the second accessory pin during the attachment process;

FIG. 9 shows a coupler in accordance with a second embodiment of the present invention with a cutaway view within the blocking bar thereof and with the actuator thereof shown in phantom;

FIGS. 10 and 11 provide further views of the blocking bar of this second embodiment;

FIGS. 12 to 14 show steps involved in a disengagement of an accessory from the coupler of this second embodiment with the coupler in an inverted orientation;

FIGS. 15 and 16 show a further embodiment, in which the arm of the first latching mechanism is elastic; and

FIGS. 17 to 19 show a further embodiment, also in which the arm of the first latching mechanism is elastic.

DETAILED DESCRIPTION OF THE INVENTION

Referring first of all to FIG. 1, there is shown a coupler 10 having a first half 12 for mounting onto an end of an excavator arm of an excavator (not shown) and a bottom half 14 in which is mounted the working mechanisms of the coupler 10. In this illustrated embodiment, the top half 12 of the coupler 10 is mounted onto the excavator arm of the excavator by a pair of accessory pins (not shown), as is conventional for excavator couplers and accessories. Other known mechanisms for mounting couplers to an excavator arm can also be used instead, by making appropriate changes to the top half of the coupler.

The bottom half 14 of the coupler accommodates the working mechanism of the coupler 10. It consists of a first jaw 18 having an opening 20 at or near the front 22 of the coupler 10. That opening faces the forwards direction relative to the coupler. The first jaw 18 is for receiving a first accessory pin or accessory attachment member of an accessory, such as an excavator bucket.

Towards the rear of the coupler, there is provided a second jaw, or a second accessory engagement area 26. That second jaw 26 has an opening that faces downwards relative to the coupler 10 and is for receiving a second accessory pin or accessory attachment member 25.

The first jaw 18 is associated with a first latching mechanism 28, whereas the second jaw 26 is associated with a second latching mechanism 30. The first and second latching mechanisms 28, 30 are shown to be hingedly mounted onto the frame 32 of the coupler 10 by hinge pins 34, 36. Those hinge pins 34, 36 extend transversely through the bottom half of the coupler. It should be appreciated, however, that in alternative embodiments, the hinge pins might extend through the frame of the coupler in the top half 12 of the coupler 10, dependent on the specific configuration of the relative jaws 18, 26, the latching mechanisms 28, 30 and the frame 32 of the coupler 10.

The first latching mechanism 28 comprises toggle latch having a latching plate 38 through which the hinge pin 34 passes. That latching plate 38 has a latching surface 40 that surface faces generally rearwardly relative to the coupler. In its latching position, that latching surface extends at least part way across the opening 20 of the first jaw 18 so as to close the first jaw 18. However, when the latching mechanism is lifted into a non latching position, that latching plate 38, and the latching surface 40 thereof, become retracted into a top wall of the first jaw 18 so as to open the opening 20 of the first jaw.

Integrally formed with that latching plate 38 is an arm 42. That arm 42 has a free end 44 that can be made thicker than the rest of the arm 42 so as to give it a heavy end. That heavy end moves the latch's centre of gravity whereby the arm 42, and the latching plate 38, readily move about their hinge pin 34 under the influence of gravity. As such, that latching mechanism will tend to move towards a closed or latching position whenever the coupler is in a normal, substantially horizontal, orientation. Likewise it will tend towards an unlatching position when the coupler is inverted. This arrangement helps with the smooth operation of the working mechanism of the coupler. It should be observed, however, that the engagement of the free end of the arm with the second latching mechanism restricts the free movement of the arm and the first latching mechanism, as discussed below.

Referring again to FIG. 1, the underside 46 of the arm 42 is cut out. This serves to cause the latching surface to extend out of the plane of the arm. Further, that underside 46 of the arm 42 is adapted to restrict the downward motion of the arm 42 relative to the frame of the coupler—it will fall down into engagement with an inside face of the frame (or an inner surface of the body or of the jaw 18).

The upper side 48 of the arm also defines a motion limiting surface for the arm since in its uppermost position that upper side 48 engages against a bearing 50 for a hinge pin 52 of the coupler's primary actuator. In some embodiments, the upper side 48 of the arm 42 might have a cut-away portion in it to allow a greater range of movement for the arm 42. However, in the illustrated embodiment, such a cut out is replaced by giving the bearing 50 a cut-away surface instead, whereupon that bearing is non-circular. In other embodiments, both cut-outs might be desirable, on no cut outs might be needed, all dependent upon the configuration of the various moving elements, and the range of motions required.

The cut out surface of that bearing 50 is fitted with one or more magnets 80 (see FIGS. 2 and 3) for holding or pulling against the upper side 48 of the arm 42. The magnets serve to ensure that the arm, when in the lifted condition (as shown in FIG. 1, is lifted fully into engagement with the bearing 50. This is to ensure that the latching surface 40 of the first latch 28 is lifted clear of, or into, the top wall of the first jaw 18. A pin within that jaw 18 thus will not foul against the latch 28 when being inserted into or retracted from the jaw 18.

As discussed above, the primary actuator 54 of the coupler 10 is mounted on a hinge pin 52. That hinge pin, in this embodiment, extends parallel to the two previously described hinge pins 34, 36. As such it is likewise mounted to the frame 32 of the coupler 10. A pivotal mounting of the actuator relative to the frame of the coupler is to allow the actuator 54 to pivot relative to the frame 32 as it operates the working mechanism of the coupler 10. The hinge pin 52 is extending through or into the bearing 50, and a correspondingly located bearing on the other side of the frame.

In this illustrated embodiment, that actuator 54 is a hydraulic cylinder with a dual acting piston for both driving and retracting the second latching mechanism 30 between its latching position and its unlatching position. Such hydraulic cylinders are well known in the art. They have one end pivotally attached to the frame by a hinge pin, as discussed above, and a second end pivotally mounted onto a second hinge pin 56, this time located on the second latching mechanism 30. As a result, the latching mechanism 30 is operatively connected to the actuator 54 for movement relative to the frame.

Instead of an hydraulic actuator, other forms of actuator can be provided, such as screw thread actuators, or hydraulic motors.

In this embodiment, a blocking bar 58 is also mounted onto the hinge pin 52 for the actuator 54. That blocking bar is adapted to be selectively biased into a blocking position by a spring 60. The operation of this type of blocking bar 58 is described, for example, in GB 2330570. However, in the present invention, that blocking bar does not just serve to restrict movement of the second latching mechanism; it additionally restricts movement of the first latching member! That is by means of the inter-relationship between the first and second latching mechanisms, as discussed below. Nevertheless, it has many similar features to the prior art blocking bars. For example, the rear of the second latching mechanism has, at least at the part that aligns with the blocking bar 58, a stepped surface 62. This allows the blocking bar 58 to block the second latching mechanism 30 in a selection of different positions relative to the frame. As a result, the blocking bar can provide a blocking function for the second latching mechanism for a number of different buckets or accessories 16, each having different accessory pin centers (i.e. different pin centre to pin centre spacings), as occurs between different accessory manufacturers.

It will be appreciate, however, that an alternative construction might place the stepped surface onto the end of the blocking bar, rather than on the second latching mechanism.

Referring next to the second latching mechanism, it basically consists of a pivoting latching hook mounted for pivotal movement relative to the frame 32 of the coupler 10 on the hinge pin 36, and driven by the actuator 54, all as described above. Many of its features, in that regard, are similar to prior art arrangements. However, the rear of that latching mechanism has been changed so as to be bifurcated such that one half has the stepped surface 62 for interaction with the blocking bar, whereas the second half has a rearwardly extending flange of finger 66 for restricting or causing movements of the arm 42 of the first latching mechanism 28. This is achieved since the free end of that arm can engage thereagainst, for example as the second latching mechanism 30 is moved from an open position into a latching position.

The rear of the second latching mechanism 30 also has a knuckle 68 that faces that flange or finger 66, thereby providing two generally opposed bearing surfaces—one for opening the first latching mechanism and one for closing the first latching mechanism, as discussed below.

Between the knuckle and the flange or finger, there is defined a groove into which the free end of the arm may extend, such as during the movement of the second latching mechanism. That knuckle 68 therefore provides a bearing surface that serves to engage the free end 44 of the arm 42 of the first latching mechanism for causing that arm to lift as the second latching mechanism is retracted by the actuator. This in turn means that both the front and rear jaws of the coupler are opened substantially simultaneously 18.

It will therefore be appreciated that the flange (or finger) 66 and the knuckle 68 serve together to cooperate with the free end 44 of the arm 42 for opening and closing the front jaw as the second latching mechanism (i.e. the rear hook 30) moves.

Further, as the hook 30 is powered back towards a closed position, the finger 66 bears against the upper surface 48 of the arm 42, thus breaking the magnetic hold between the magnet(s) 80 and the upper surface 48 of the arm 42.

Referring now to FIG. 5, which shows the fully engaged coupler on a bucket, that interaction between the shoulder 68 and the free end of the arm 42 is not by default achievable—the retraction of the hook 30 is blocked initially by the blocking bar, and failing that it is also blocked by the location of the free end 44 of the arm 42—below the knuckle 68. Therefore that interaction between the knuckle and the free end 44 of the arm 42 is only achievable when both 1) the blocking bar 58 is not preventing retraction of that hook 30 by its free end engaging the stepped surfaces 62 of the hook 30 and 2) the arm 42 has been “lifted” away from its default rest position. These two actions both occur only when the coupler is inverted into a crowd position—see FIGS. 2 and 6, as explained below.

The operation of the coupler 10 of the present invention will now be discussed with reference to the two sequences of Figures: FIGS. 2, 3 and 4, and then FIGS. 5, 6 and 7.

FIGS. 2 to 4 illustrate an accessory connecting procedure. Referring first of all to FIG. 2, the coupler 10 is manipulated by the excavator's excavator arm and hydraulics into a fully crowded position, or the crowd position. This position allows both the blocking bar 58 to disengage from the stepped surfaces 62 of the second latching mechanism 30, and the free end 44 of the arm 42 to “lift” above the shoulder, both due to gravity. It should be observed that this crowd position does not engage the spring 60 against the arm of the excavator—that spring 60 only engages against the arm of the excavator when the coupler is oppositely rotated, i.e. towards a fully extended position with respect to the excavator arm.

Once inverted into the crowd position, the second latching mechanism 30 can be retracted using the actuator 54 (it is no longer blocked from such movement by either the arm 42 or the blocking bar 58). As that second latching mechanism is retracted into its open position, its shoulder will engage against the underside of the free end of the arm (if the arm fails to free-swing under the influence of gravity) to thereby not just open the second jaw 26, but also the first jaw 18. The coupler's jaws will therefore both fully open.

In preferred embodiments, a control mechanism can sense this position (e.g. via sensors in the hydraulics, or in the coupler) and cause a buzzer to sound in the cab of the excavator for informing the operator of this condition.

From this condition, in which the retracted second latching mechanism 30 will hold both the blocking bar 58 and the first latching mechanism 28 in their open positions irrespective of the orientation of the coupler, the coupler can be reoriented such that its front jaw 18 can be engaged upon a first accessory pin 24 of an accessory 16. This is shown in FIG. 3. That step is step 2 of the connection procedure.

Then, as shown in FIG. 4, step 3 of the connection procedure is performed to complete the connection procedure. That third step involves rotating the coupler once again towards the crowd position for lifting the accessory 16 with the front jaw 18, whereupon the second accessory pin 25 of the accessory 16 will engage into the open second jaw 26 of the coupler 10. Then the actuator 54 (the hydraulic ram) can be extended again to drive the second latching mechanism 30 into its latching condition against the second accessory pin 25. That in turn will cause the flange or finger 66 to push the free end 44 of the arm 42 of the first latching mechanism 28 so as also to close the first latching mechanism relative to the first jaw 18. The coupling procedure is then complete, and upon returning the coupler to the normal use orientation, both the blocking bar and the arm 42 will fall under the influence of gravity into their rest, or blocking positions.

It should also be observed that the flange or finger 66 of the hook 30 will hold that first latching mechanism in its closed position, whereby the first accessory pin is for certain secured, even if the second accessory pin failed to engage into the second jaw. This is described again below with reference to FIG. 8.

Referring next to FIG. 5, the fully locked coupler is shown with its blocking bar 58 once again fallen into a blocking position behind the second latching mechanism 30, and with the first latching mechanism 28 in a fully dropped position, with its free end 44 below the shoulder 68. The accessory 16 is thus fully secured onto the coupler 10. For example, the possibility of accidentally opening the jaws of the coupler is prevented until the coupler assumes the crowd position. In that regard, the inadvertent opening of the first latching mechanism is restricted by the flange or finger 66 blocking its path, and the second latching mechanism 30 also being locked in a latching position against its respective accessory pin 25 by both the blocking bar 58 (as the primarily blocking mechanism since it blocks almost all rearward travel of the second latching mechanism 30 by view of its free end opposing the stepped face 62 at the rear of the latching mechanism 30) and the free end of the arm (in the event that the blocking bar fails to engage properly).

Referring next to the sequence of FIGS. 5 to 7, a decoupling procedure will now be described.

From the normal working condition of FIG. 5, an operator first moves the coupler and accessory 16 into a crowd position underneath the excavator arm, as shown in FIG. 6. This is to allow or cause the blocking bar to fall out of its blocking position, and to allow the arm to move into a position “above” the shoulder 68 of the second latching mechanism. These positions are all shown in FIG. 6.

Upon reaching this condition, the actuator or hydraulic ram 54 can be used to retract the second latching mechanism 30, and thus also to “lift” or open the first latching mechanism 28. Thus the front jaw and the rear jaw open roughly simultaneously. The magnet(s) 80 may also “help” with the opening of the front latch 28, at least once the upper surface 48 of the arm 42 is near enough to the magnet(s) 80.

The alarm in the cab may be just to notify the user of this crowd condition, but as discussed above for the coupling procedure, it is preferred that the system is instead arranged to sense that the jaws are both open (e.g. using the above mentioned sensors) and to then sound the alarm for that condition. This is to ensure that the operator closes the jaws (to turn off the buzzer).

In this condition, the actuator holds the second latching mechanism in its open position and thus also the first latching mechanism also in its open position. Therefore, the accessory 16 and coupler 10 can be rotated back out of the crowd position so as to place the bucket or accessory 16 gently on the ground. Then the coupler can simply be manipulated relative to that accessory (which being on the ground is deemed to be made safe) so as to decouple the coupler from the accessory and to move the coupler 10 away from the accessory 16. The dismounting procedure is thus completed, with the coupler already primed and ready for mounting onto the next accessory (since it is already in the condition of FIG. 3—all jaws open).

It will be appreciated from the above, therefore, that the present invention provides a coupler that offers very rapid and easy mounting and dismounting of accessories thereto, but without presenting the opportunity for accidental dismounting procedures to be carried out. This is because the crowd position (a position not usually used during the conventional use of an accessory) is needed to be used before a dismounting procedure can commence.

Then, referring to FIG. 8, an additional safety benefit of the present invention is shown. Here, a situation is illustrated where an operator error has occurred—the attachment procedure has been followed, but without correctly engaging the second accessory pin 25 in the second jaw 26 of the coupler 10. As such, the second latching mechanism 30 has been advanced into a “latching” position (e.g. to turn off the buzzer in the cab), but without capturing the second accessory pin 25. This type of error traditionally presented a dangerous situation since without a securement mechanism for the front jaw, the first accessory pin was free to fall out of the front jaw 18. However, with this invention, the first accessory pin 24 is securely locked into the front jaw 18 by the first latching mechanism 28, which is closed. Further, because of the finger 66 on the second latching mechanism, movement of that first latching member 28 is restricted such that it cannot move out of a latching position. As such, the pin 24 that is located in the first jaw 18 cannot be removed from the jaw 18 other than by recycling through the latching/dismounting procedure. Therefore, the operator is given an opportunity to spot and correct the incorrect mounting of the accessory on the coupler before further use of the accessory commences and without any risk of dropping the accessory off the coupler.

Referring next to FIG. 9, an alternative embodiment of the present invention is disclosed. This embodiment again has a blocking bar 158 and a separate front latch with an arm extending therefrom towards a rear latch 30. The actuator (hydraulic ram) for operating the rear latch 30, however, is only shown in phantom. This is for clarity since differences between the previous embodiment and this embodiment reside in the design of the blocking bar 158.

As can be seen, this blocking bar 158 has a hydraulic ram 162 provided in its bottom half—it is located within a chamber 160. It also features a coil spring (not shown) for keeping it biased towards a blocking position. The blocking bar and its hydraulic ram 162 is shown in greater detail in FIGS. 10 and 11, with FIG. 10 showing the whole blocking bar 158 and FIG. 11 being a partial cutaway view through the blocking bar 158, the cut being substantially along the blocking bar's longitudinal axis.

This alternative blocking bar is similar in operation to the blocking bar 58 of the previous embodiment. However, rather than being a solid blocking bar, it has a chamber 160 provided therein for accommodating a hydraulic cylinder 162. The hydraulic cylinder 162 is mounted within the chamber 160 along an axis substantially parallel to, but spaced from, the longitudinal axis of the blocking bar 158. However, as before it can be mounted differently, e.g. in a chamber pointing in a different direction. It has a free end 164 also lying on that axis of the cylinder 162. That cylinder 162, by being spaced away from the longitudinal axis of the blocking bar 158 is so spaced so as not to be coincident with the hinge axis of the blocking bar 158, as defined by the centre of the hinge pin 166, e.g. as shown in FIG. 9. As such, as the free end of the hydraulic cylinder can bear against a fixed element, such as a cut-out (not shown) on that hinge pin 166, whereby that cylinder 162 can cause the blocking bar to be lifted from its blocking position (similar to that shown in FIG. 9) to its non-blocking position (similar to that shown in FIGS. 13 and 14). The hydraulic cylinder 162 can therefore raise the blocking bar from a blocking position into a non-blocking position.

Hydraulic fluid can be supplied to the cylinder 162 through the port 170 that is located at the top of the blocking bar 158. A separate hydraulic fluid supply pipe can be connected to that port, controlled by a separate solenoid valve and a separate switch in the cab of the excavator (not shown), each being separate to similar arrangements provided for the primary actuator 54 of the coupler. The return pipes to the fluid reservoir (not shown), however, can follow a common route, or can be fluidly connected to follow a common return pipe. The two hydraulic power supplies to the two hydraulic actuators are described as being controlled independent to one another, however, for minimizing the possibility of an accidental release.

For maintaining the blocking bar in a blocking position (i.e. when the hydraulic cylinder is not being powered), a spring is provided for the blocking bar. That spring can be inside the hydraulic cylinder for forcing a compression of the cylinder 162. Alternatively a ring spring can be provided within the bearing sleeve 168 of the blocking bar. Other arrangements are also possible for biasing the blocking bar towards a blocking position. With this arrangement a dual acting (i.e. bi-directional) hydraulic cylinder is not required for the blocking bar, although it can be provided if desired. The spring can then be provided as well, as a back-up safety measure.

As for the arm 42 of the first latching mechanism 28, it is still arranged to be engageable by the second latching mechanism 30 such that the second latching mechanism 30 can lift it to open the first latching mechanism 28. This might be achieved with a ramped surface on the second latching mechanism that faces towards the free end of the arm (not shown), or it can be achieved by the geometry of the facing surfaces at the point of contact therebetween (not shown) and such design details would be within the ambit of a skilled person. For example, see GB0816498.6 for details of a ramped rear surface for the second latching mechanism. With this arrangement, there is no requirement for the coupler to be inverted in order to decouple an accessory from the coupler—both the arm and the blocking bar can be lifted into a non-blocking position remotely by the powered systems of the coupler—the blocking bar is lifted by its hydraulic actuator, whereas the arm 42 of the front latch can be lifted by the rear of the rear hook 30. This coupler can thus be used for changing accessories even in situations where inversion of the coupler is impossible or difficult, such as in tunnels or in other places where vertical headroom is limited—as explained previously, for achieving a crowd position, the elbow of the arm of the excavator needs to point upwards, whereby it is raised above the cab of the excavator.

It should also be observed that a remote lifting mechanism might also be provided for the arm of the first latching mechanism, such as a further hydraulic ram, controlled by a further circuit, so as to be further independent to the others.

An advantage of this biased blocking bar arrangement can also be observed from FIG. 12: in this embodiment an inversion of the coupler will not always cause the blocking bar to move to a non-latching position, whereby the spring for acting against the arm of the excavator can be removed. Further, an accidental positioning of the coupler into the crowd position will not put the coupler into an “accessory releasable” condition. After all, such a condition can now only occur upon powering the blocking bar's counter biasing means—the hydraulic cylinder 162 (see FIG. 13 where that hydraulic ram/cylinder/actuator has been extended for “lifting” the blocking bar into its non blocking position). Only then can the rear hook be powered into the open position, as shown in FIG. 14.

A magnet 80 can again be present in the bearing 50 for the purpose discussed above.

Referring next to FIGS. 15 and 16, a further embodiment of coupler is shown. This embodiment has similarities to the original embodiment in that it has a pivoting rear latching hook 30, a blocking bar 58, a front latch 28 and two jaws 18, 26. Further, the blocking bar 58 is provided with a spring 60 for selectively biasing it into a closed, blocking position as shown in FIG. 15, upon engagement of that spring 60 against the arm of the excavator—which occurs when the coupler ex inverted into an extended condition, but not when the coupler is inverted into a crowd position. Likewise, magnets 80 are provided in the bearing 50. However, the designs of the first and second latching mechanisms 30, 28 are different.

The design of the second latching mechanism, the rear hook 30, is still provided with a finger 66 for engaging a free end of an arm 42 of the first latching mechanism 28. However, that finger 66 extends slightly further towards the front end of the coupler—i.e. further towards the first latching mechanism. This allows the arm 42 of the first latching mechanism to be fractionally shorter than before, whereby it will not foul against a knuckle 68 of the hook 30 in a blocking manner. This feature, however, is optional. Preferably, however, the free end facing surface of that hook 30 (but not the finger 66) can be designed still to engage against the free end 44 of the arm 42, but in a manner that causes the first latching mechanism to open into a non latching position. This can occur as the hook 30 is retracted by having the arm resiliently flexible such that it will flex upwardly, thus pivoting the first latching mechanism about its pivot pin 34. To allow that flexing, the arm 42 is preferably formed from a resilient, flexible material, such as spring steel or a series of plates of spring steel.

Where a series of plates of spring steel are provided, an end capping member, as shown, can be provided to hold those steel plates together at the free end 44. A similar end capping member can also be provided at the free end of the spring 60, as provided for the blocking bar, since it too can be a series of spring steel plates.

The finger 66 of the hook 30, however, is still arranged to control the range of motion of the arm 44 so as to not allow it readily to lift into a raised condition, even if the coupler is inverted, since it is desirable to keep both jaws closed unless a decision is taken to release the accessory. However, upon powering back the hook 30 into a non latching position, the first latching mechanism can be opened. First, however, the blocking bar needs to be released to allow that movement of the hook 30.

The first latching mechanism is also different to that shown in a previous embodiment. That is because, as described above, it has an arm 42 that is formed of a resilient, flexible material. This resilient, flexible material, e.g. the steel plates, is bolted onto a latching component of the first latching mechanism 28. As a result, those two components can be formed of different materials—the latching component of the first latching mechanism 28 is preferably formed from a hard, stiff or tough material, such as hardened steel, so as to be able to resist attempts to remove an attachment pin 24 from within the first jaw 18 while the first latching mechanism 28 is in a closed position.

Because the arm 42 is flexible, it is preferred that an additional stop arm 138 is provided for the latching component of the first latching mechanism 28. This stop arm 138 is preferably integral to the main body of the latching component such that that latching component can be of a one piece construction. The stop arm 138 provides a flange that is adapted to engage against the main structure of the jaw 18 so as to restrict the degree of rotation available for that latching component about its pivot pin 34. This therefore prevents an overloading of the resilient arm 42 in that that arm 42 does not serve as a stop for the rotation of the first latching mechanism 28.

Operation of this coupler is generally similar to that of the original embodiment of FIG. 1. In use, the coupler is inverted into the crowd position to allow gravity to cause the blocking bar 58 to drop into a non blocking position and such that the free end 44 of the arm 42 will fall to rest against the finger 66 of the rear hook 30. Then, the rear hook 30 is powered backwards by the actuator 54 so as to open the rear jaw 26. This in turn allows the arm 42 of the first latching mechanism also to rotate about the first latching mechanism's pivot axis 34 and thus the first jaw 18 also opens. The upper surface 48 of the arm 48 then is held in the open position by the magnet(s) 80 on the bearing 50. This ensures that the front jaw 18 is fully open, i.e. that the latching component's bottom edge 82 is pulled up and into the top surface of that jaw 18.

Once open, the rear jaw 30 is retained in its open position whereby its back can hold the arm 42 in its non-latching position and the coupler can then be coupled onto an accessory by locating a first attachment pin 24 thereof in the first jaw 18 and then a second attachment pin 25 thereof in the second jaw 26. Then, the rear hook 30 can be powered back into a latching position so as to allow the first latching mechanism to close the first jaw 18 (upon the finger 66 pinging the arm 42 off the magnet(s) 80). The accessory is thus now fully and securely coupled onto the coupler. Further, since in locating the second attachment pin 25 into the rear jaw 26, the coupler will have been reinverted into a normal upright configuration, the blocking bar 58 will fall once again into position behind the relevant part of the rear hook 30, thus restoring its blocking condition (at least until the coupler is again returned into a crowd position (for releasing the blocked bar—the spring 60 provides the necessary biasing force for the blocking bar).

It is also to be appreciated that a powered blocking bar, as per the embodiment of FIG. 9, can be provided in this embodiment, in place of the gravity operated blocking bar shown. The rear of the hook 30 would then want to be shaped to lift, or flex the arm of the first latching mechanism, as already described above in relation to other possible arrangements if a non inversion version is desired. Such a configuration would then allow an accessory to be uncoupled from the coupler even while the coupler is in a horizontal, non-inverted, orientation, whereby the coupler can more readily be used in situations where inversion is made difficult (e.g. by height restrictions, or by the shape of the accessory—i.e. where it is too long to be moved into the crowd position). Such situations include large tools (i.e. ones that cannot assume a crowd condition due to their long length), rail and tunnel environments (where a low roof height prevents the folding of the arm), and situations where overhead power lines are located (where the arm would not want to be so folded).

To dismount an accessory from the coupler of FIG. 15, again the coupler is inverted into the crowd position, and the rear hook 30 is powered into an open position. This again opens the front jaw whereupon the accessory can then be decoupled therefrom.

Finally, referring now to FIGS. 17 to 19, a further embodiment of coupler is shown schematically for illustrating a further arrangement that can be provided for the magnet 80.

This last embodiment has similarities to that shown in FIGS. 15 and 16. Further, the frame is again cut-away to facilitate the viewing of the internal mechanism of the coupler. Indeed, in FIG. 19 the frame has been hidden completely.

In this embodiment, the general mode of operation is the same as before. For example, there is still a finger 66 on the back of the rear hook 30. Further, there is a flexible arm 42 on the front latch 28. However, whereas before the magnet(s) 80 were mounted within the bearing 50, the magnets are now provided further along relative to the arm 42—in a specially provided bracket 86 that is fixedly mounted relative to the frame.

The positioning of the magnet 80 further along the arm—here roughly half way along it—and preferably it is located at least half way along it towards the free end thereof, the magnet has a greater retention moment on the arm 42. It thus will be less likely to release the arm 42 if the coupler is shaken violently. The finger 66 though still pings the arm 42 off the magnet 80 when it comes to close the rear jaw 26.

In conclusion, therefore, it is a preferred arrangement for the invention to provide: a coupler 10 comprising first and second jaws 18, 26 for receiving first and second attachment pins 24, 25 of an accessory 16 wherein a first latching mechanism 28 is associated with the first jaw 18, the first latching member having an arm 42 operatively connected to and extending away from a latching member 38 thereof, and a second latching mechanism 30 is associated with the jaw 26, and the first and second latching mechanisms 28, 30 being adapted to latch the first and second accessory pins 24, 25 of an accessory 16 in or on the first jaw 18 and the second jaw 26, respectively; and wherein the second latching mechanism 30 is powered for movement between a latching position and a non-latching position and the first latching mechanism 28 is operatively connected to, or connectable with, the second latching mechanism 30 to allow operation of the second latching mechanism 30 selectively to operate the first latching mechanism 28 between its own latching and non-latching positions by means of a groove or flange or finger 66 provided on the second latching mechanism 30. A magnet 80 is also provided to ensure a correct disengagement of the first latch latching mechanism, when required.

Finally, referring to FIG. 20 a modified version of the coupler according to FIG. 5 is shown. This coupler is modified to be no longer an automatic coupler. Instead it is a semi-automatic coupler. The coupler has been modified in a non-intuitive way to include safety pins—a feature that historically the blocking bar and other safety elements were striving to replace.

The purpose of the use of safety pins is to allow there to be a final mechanical securement of the latched state of the coupler upon completion of a latching procedure. It therefore acts as a final guarantee that the accessory cannot accidentally be decoupled from the coupler. There are occasions when such a guarantee is desired.

As shown in FIG. 20, there is a hole 150 provided in the front of the frame of the coupler 10. That hole is for receiving a first safety pin, such as one disclosed in EP0405813. The entire contents of that document is incorporated herein purely by way of reference since it assists in explaining the functionality of such a safety pin in the context of couplers, and a non-mechanical latch therefore. That prior art document, however, relates to front loaders, rather than excavators, whereby the orientation of the various elements thereof are incompatible with a coupler for an excavator arm of an excavator. Further, the safety pin, in securing its latch in that prior art document acts as a primary means for securing the latch in a closed orientation—something that is not required in the present invention since that front latch is instead merely a secondary safety mechanism, rather than a primary means of securement for an accessory—the primary securement is instead performed by the powered latch 30. It is therefore counter-intuitive to add the safety pin from that prior art document into the coupler of the present invention. Nevertheless, there are situations, as mentioned above, where a further level of securement might be called for, and it is for this purpose that this further embodiment is provided.

Returning to the present invention, from FIG. 20 it will be appreciated that upon locating a safety pin in the hole 150, the front latch 28 is resisted from raising into a non latching position by the safety pin—even if the coupler was to be inverted, and the finger 66 was to be absent or broken. The safety pin can therefore provide an additional level of safety for the coupler.

In addition to that first safety pin, a second safety pin arrangement is provided. This second safety pin arrangement may be in addition to the first safety pin, or it may be instead of the first safety pin.

Referring again to FIG. 20 there is shown a latch-hole 152 in the rear latch 30. There is also a hole (not shown) in the side wall of the frame of the coupler over which the hole 152 in the latch is in alignment. Indeed, there is a pair of holes in the sidewalls of the coupler, whereby that latch-hole 152 is for receiving a safety pin through both of the holes in the sidewalls and the hole 150 in the latch. Such a safety pin can be like those disclosed in either one of documents GB2359062 or GB2419341, the entire contents of which are incorporated herein purely by way of reference since they too can assist in explaining the functionality of such a safety pin in the context of couplers, here though in relation to a powered latch. Those prior art documents, however, rely upon the safety pin for maintaining the powered latch in a closed position, and whereas the safety pins here would again perform that purpose, that purpose is effectively made redundant by the presence of a) the front latch 28, b) the blocking bar 58, and c) the interrelationship between the free end of the arm 42 of the front latch 28 and the finger 66 on the back of the powered hatch 30. As such, as with the first safety pin, this second safety pin arrangement's presence is counterintuitive. Nevertheless, the safety pin does again provide an additional level of safety for the coupler, when called for by a customer.

Still referring to FIG. 20, there is also a second hole 154 (or pair of holes) in the sidewalls of the coupler 10. This hole (or holes) is also for receiving a safety pin (not shown, but instead when the latch 30 has been further advanced across the opening of the jaw 26 associated therewith. In that case the safety pin would have been removed from the first hole 152 (to allow the rotation of the latch 30), and upon the second hole 154 being cleared by the rear edge of the latch 30, the safety pin can be reinserted, but instead in this second hole 154 (or second pair of holes). The safety pin will thus again secure the latch 30, but instead in that more advanced position.

The blocking bar may have also ratcheted down onto a further step of the rear of that latch 30 (see FIG. 1 for the steps).

Preferably the positions of the holes in the sidewalls are located so as to coincide with the ratcheting down of the blocking bar over those steps.

This illustrated arrangement also offers a third condition for the safety pin, again upon removing the safety pin and further advancing the latch 30 across the opening of the jaw 26. Such further advancement will not just cause a final ratchet of the blocking bar to occur—it will also cause the first hole (or pair of holes) in the sidewall(s) of the coupler to become available at the back of the latch 30. As such, the safety pin, upon reinsertion into that or those first hole(s) will secure the latch 30 in a third position—with the pin again being adapted to rest against the outside or rear surface of the latch 30, as in the second arrangement, rather than through the hole 152, as in the first arrangement.

The provision of two pairs of holes in the sidewalls plus a single hole in the hook 30, has thus achieved three secured conditions for that hook 30 with the use of just one safety pin.

Further arrangements for safety pins for this purpose are disclosed in GB2359062 or GB2419341, the contents of which are incorporated by reference any of which can be used with the present invention.

It will of course be apparent to a skilled person that elements of one embodiment can be adapted for use with the other embodiments. For example, the sprung arm 42 could be used to replace the arms 42 in the other embodiments. Further, the powered blocking bar can be used in other embodiments, again as described above.

The present invention has therefore been described above purely by way of example. Modifications in detail may be made to the invention within the scope of the claims appended hereto. 

1. A coupler having a top half for attaching to an end of an excavator arm of an excavator and a bottom half for attaching to an accessory, the bottom half comprising first, front jaw and a second, rear jaw, at least one of the jaws featuring an associated latching mechanism for retaining an attachment pin of the accessory within the jaw, wherein one of the coupler, one or both of the jaws, and the associated latching mechanism further comprises, or is associated with, a magnet, the magnet configured for releasably engaging or holding a component of the locking mechanism in a predefined positional condition relative to one of the jaws or relative to another component of the latching mechanism.
 2. The coupler of claim 1, wherein the latching mechanism is associated with the first jaw, and the first latching member comprises an arm operatively connected to and extending away from a latching member thereof.
 3. The coupler of claim 1, wherein at least one latching mechanism of the coupler is powered for movement between a latching position and a non-latching position.
 4. The coupler of claim 1, comprising two latching mechanisms, one for each jaw.
 5. The coupler of claim 4, wherein a first of the latching mechanisms is operatively connected to, or connectable with, a second of the latching mechanisms to allow operation of the second latching mechanism selectively to operate the first latching mechanism between its own latching and non-latching positions.
 6. The coupler of claim 5, wherein the second latching mechanism comprises one of a groove, a flange and a finger for defining a space or surface in or on which a free end of an arm of the first latching mechanism can reside during either or both a coupling and/or a decoupling procedure of the coupler for allowing the movement of the second latching mechanism to operate the first latching mechanism between its latching position and its non-latching position.
 7. The coupler of claim 6, wherein movement of the second latching mechanism to operate the first latching mechanism from its non-latching position into its latching position will disengage the magnet from the component.
 8. The coupler of claim 6, wherein as the second latching mechanism is powered into a non-latching position, the free end of the arm of the first latching mechanism, upon engagement by the second latching mechanism, is lifted by the movement of the second latching mechanism, so as to lift a latching face of the first latching mechanism into a non-latching position, and as the second latching mechanism is powered into a non-latching position, the free end of the arm of the first latching mechanism, upon engagement by the second latching mechanism, is lifted by the movement of the second latching mechanism, so as to lift the component into interaction with the magnet.
 9. The coupler of claim 1, wherein the first latching mechanism comprises a rocker latch for partially closing the first jaw when in a “dropped” or jaw closing position.
 10. The coupler of claim 9, comprising an arm extending from the rocker latch or a latching plate thereof, and the arm of the first latching mechanism extends within the coupler inside the framework or frame of the coupler towards a second latching mechanism.
 11. The coupler of claim 10, wherein the arm is the component that the magnet can releasably engage or hold.
 12. The coupler of claim 1, wherein the rear jaw has an opening pointing generally perpendicular to the longitudinal axis of the coupler, the opening being at least 1.8 times wider than the opening of the front jaw.
 13. A coupler having a top half for attaching to an end of an excavator arm of an excavator and a bottom half for attaching to an accessory, the bottom half comprising first, front jaw and second, rear jaw, each of the jaws comprising an associated latching mechanism for retaining an attachment pin of the accessory within the associated jaw, wherein the coupler further comprises a safety pin for securing at least one of the latching mechanisms in a latching state with respect to the associated attachment pin.
 14. The coupler of claim 13, wherein the safety pin is arranged to pass through either one or both sidewalls of a frame of the coupler.
 15. The coupler of claim 13, adapted such that the safety pin can lock the associated latching mechanism in any one of multiple pin locking positions for accommodating and securing accessories having different pin spacings.
 16. The coupler of claim 15, wherein the second jaw has an opening pointing generally perpendicular to the longitudinal axis of the coupler, the opening being at least 1.8 times wider than the opening of the first jaw.
 17. The coupler of claim 15, wherein multiple holes are provided in the coupler's sidewall, or in the coupler's sidewalls, for receiving the safety pin.
 18. The coupler of claim 14, wherein a hole is provided in the associated latching mechanism for receiving the safety pin.
 19. The coupler of claim 13, wherein the safety pin has a portion with a non circular cross section, whereby the shape of the safety pin allows it to lock or secure the latching mechanism in a variety of different locking positions dependent upon the orientation of the safety pin within a given hole or pair of holes in the coupler.
 20. The coupler of claim 13, wherein a first of the latching mechanisms is operatively connected to, or connectable with, a second of the latching mechanism to allow operation of the second latching mechanism selectively to operate the first latching mechanism between its own latching and non-latching positions. 